President Donald Trump once reportedly took another player's golf ball to cheat and win a club championship in 2018, according to the author of a new book who spoke with members at the club.

According to the sportswriter Rick Reilly, whose new book "Commander in Cheat" explores Trump's relationship with golf and how it may inform his presidency, Trump's desire to win goes even further than we had previously known.

Trump had missed the club championship at his Trump International course in Florida while meeting with North Korean leader Kim Jong Un in Singapore.

About a month later, Trump was back at Trump International when he saw Ted Virtue, an investor who is a member of the club and had won the championship while Trump was away. Virtue was playing with his son when Trump rode his cart over to them at the 12th hole.

Trump joked that Virtue won his championship only because he had been out of town and then challenged him to play the final six holes of the course for the title, according to the story Reilly told to Vox. Then things really got weird.

Reilly, who verified the story with members of the club, told the following story to Vox's Illing:

Ted tries to laugh it off, but Trump is dead serious. Trump says, "We're gonna play these last six holes for the championship." And Ted's like, "Oh, well, I'm playing with my son, but thanks anyway." But Trump says, "It's okay. Your son can play, too." So what are you going to do? He's the president. It's his course. They end up playing.

Apparently, they get to a hole with a big pond in front of the green. Both Ted and his son hit the ball on the green, but Trump hits his in the water. By the time they get to the hole, though, Trump is lining up the son's ball. Only now it's his ball and the caddie has switched it.

The son is like, "That's my ball!" But Trump's caddie goes, "No, this is the president's ball; your ball went in the water." Ted and his son look at each other confused, not sure if this is really happening.

The son was originally described as a child about "10 or 11" years old. Vox later corrected their story and noted that Virtue's sons are "at least in their 20s."

According to Golf.com, Trump told Virtue that they could be co-champions, but on Trump's locker at the club, his plaque makes no indication that he shares the title.

It's just the latest in a series of stories that have steadily come out about Trump's golf game during his presidency. Speaking with a Norwegian newspaper, the LPGA golfer Suzann Pettersen said that she had seen Trump's cheating up close.

"He cheats like hell. So I don't quite know how he is in business. They say that if you cheat at golf, you cheat at business," Pettersen said.

She continued: "He always says he is the world's best putter. But in all the times I've played him, he's never come close to breaking 80. But what's strange is that every time I talk to him, he says he just golfed a 69, or that he set a new course record or won a club championship someplace."